A conventional implantable cardiac device may be used to treat fast and/or slow arrhythmias with stimulation therapy including cardioversion, defibrillation, and pacing stimulation. Such stimulation may be prescribed when the patient's heart does not function normally due to, for example, a genetic condition.
An implanted device typically includes a telemetry interface that enables an external device to read data from the implanted device and configure the implanted device. For example, the implanted device may log data relating to the cardiac activity of the patient's heart and corrective stimulation that the implanted device applied to the heart. A treating physician may analyze this data to determine whether to modify the patient's treatment. In addition, based on this data or other tests the physician may reconfigure how the device senses cardiac activity and applies stimulation therapy.
Conventionally, the external device communicates with the implanted device or devices via radio frequency (“RF”) signals. For example, the external device connects via a lead to a telemetry head that includes an antenna. When the telemetry head is placed near the implanted device (e.g., on the patient's skin), the telemetry head may send signals to and receive signals from a corresponding telemetry circuit in the implanted device. In general, the external device may include a wireless, e.g., RF, communication element capable of communicating with the implanted devices at relative short distances, for example, two to three meters. The implantable cardiac device and/or a separate “sensor device” for monitoring indicators for heart failure exacerbation may be configured to send and receive signals from either the telemetry head or a wireless communication element.
Traditionally, the external device is used in either a clinical setting or in a patient's home. In the latter case, the external device (e.g., a call-in system) may communicate with a remote computer via a telephone line or cellular communications. In this way, an operator at a remote location may read information from the implanted device or program the implanted device.